Dispensing cartons for granular, crystalline and powdered products have been in demand by consumers for many years. Typically, manufacturers have responded by designing their cartons so that the consumer can tear open a flap or flaps through which the contained product can be dispensed, as shown, for example, in U.S. Pat. Nos. 3,270,942 which issued to Cope et al on Sept. 6, 1966; 3,894,680, issued to Araki on July 15, 1975; and 1,739,529, issued to Skinner on Dec. 17, 1929. Such cartons when made siftproof are sometimes difficult to open and, once opened, effective reclosure in most cases is difficult, if not impossible.
Another technique has been to provide a metal spout which in use is a hinged, three-sided structure mounted on a carton sidewall. These are difficult to seal initially for shipment, are generally not well adapted to dispensing of large usage amounts for products such as laundry detergent granules or the like and are expensive to manufacture and apply to cartons.
Others have responded by applying fitments to their containers, usually immediately prior or subsequent to the filling operation. For example, in U.S. Pat. No. 3,018,024 which issued to Foord on Jan. 23, 1962, the patentee provided a folded, one-piece, thermoformed container closure of the plug-within-a-plug type, snapped into a cutout in the top closure of a carton adjacent to the closure edge.
In U.S. Pat. No. 4,516,689, which issued to Barker on June 22, 1984, FIGS. 5 and 6 illustrate an attachable closure/pouring lip device which is adapted to be snapped into a dispensing aperture in the top closure of a liquid container and wherein a plug-equipped closure flap is attached to a base flap and articulated therefrom by means of an over-center hinge. In another preferred embodiment an easy-open/reclosing element is hingedly attached to the lid's outer surface and employs an over-center hinge for holding the closure element in a locked open condition while the container's contents are dispensed. A depending plug is used to seal the precut dispensing aperture in the top lid.
U.S. Pat. No. 4,579,246, which issued to Swearington et al on Apr. 1, 1986, shows a closure providing a substantially airtight and reusable seal for the entire area of the container opening using a rigid anchor member, a cover interconnectable with the opening in the anchor member and means to provide the airtight seal of the opening in the anchor member.
U.S. Pat. No. 3,250,436, which issued to Kurtz on May 10, 1966, relates to a pouring spout assembly for a dispensing container for powders, granules and crystals and illustrates the device mounted on a rectangular carton. The specification broadly states that the device can be mounted on cartons of other shape, on the top as well as the side and may be inserted at any stage of carton forming or filling, but provides no further teaching along such lines.
Despite all the prior work done in this field, there remain problems in providing an effective and economical dispensing closure for seal end cartons which are adapted to be fed into high speed production equipment. Prior art dispensing closures are not well adapted for placement on a seal end carton, particularly when the same is in flattened tubular form and, moreover, would not be highly machineable if they were so mounted on such cartons.